This invention relates to an insecticide composition for use especially as a cleansing system, and intended in particular for destroying and repelling particularly resistant insects such as fleas and ticks. Generally, the topical insecticide formulations of the present invention are suitable to use on house pets such as cats and dogs.
As most insecticidal active ingredients found in cleansing systems such as shampoos are lipophilic, their water solubility is quite limited. To obtain a homogenous and stable product, the active ingredient is generally dispersed in the cleansing system with the aid of surfactants (e.g., wetting agents, emulsifiers, dispersants, and the like). However, formulating such a dispersion is challenging and also requires a high level of surfactants to cover the large surface area. Typically, a clear shampoo usually remains clear upon dilution without the insecticide precipitating out. In addition, most cleansing systems contain one or more “cleaning agents,” which are also surfactants capable of removing lipophilic matter such as oils, from hair or skin. In addition, the amount of cleaning agent within the cleansing system is usually a high percentage of the total weight of the formulation. With this large amount of surfactant contained within the cleansing system, a substantial amount of the active ingredient is washed away with the surfactant molecules when rinsed, potentially leading to environmental contamination. This also leads to a short duration of insecticidal activity.
In view of the foregoing, there is a need for a pet cleansing system having longer duration of insecticidal activity. Further, there is a need to enhance the physical stability and aesthetics of a product as well as the uniform coverage of the active ingredient on the hair or skin, and thus it is desirable to disperse the active ingredient into a nanometer sized range within the cleansing system so that the product appears clear and homogeneous. The present invention satisfies these and other needs.